Reaction of Ru-3(CO)(12) and S(C=CSiMe3)(2) in toluene gave [Ru-3(CO)(9)(mu-eta (2)-SC=CSiMe3)(mu (3)-eta (2)-C=CSiMe3)] 1. The thermolysis of 1 provokes the rupture of the S-C-sp bond of the SC=CSiMe3 ligand and C-C coupling reactions between two acetylide groups affording the clusters [Ru-3(CO)(9)(mu (3)-S)(mu (3)-eta (2)(C(SiMe3)C(C=CSiMe3)] 2, [Ru-2(CO)(6)-(mu-eta (3)-SC=CSiMe3)(mu-eta (2)-C=CSiMe3)] 3. [Ru-4(CO)(12)(mu (4)-S)(mu-eta (2)-C=CSiMe3)(2)] 4 and [Ru-4(CO)(9)(mu -CO)(2)(mu (4)-S)(mu (4)-eta (2)- C(SiMe3)C(C=CSiMe3)] 5, All compounds have been characterized by IR and NMR techniques as well as FAB(+) mass spectrometry Crystal structures of 1, 4, and 5 have been determined by X-ray diffraction methods. The pathways of the thermolysis of 1 to give 2-5 have been investigated.